Model of Calculating Activity of Nitrogen and Vanadium in Fe-C-V-N Molten Metal

The solubility of nitrogen in the Fe-C-V-N system was measured at 1 708 K and the model of calculating activity (action concentration) of nitrogen (N) and vanadium (V) was derived according to the phase diagram and the coexistence theory of the metal melt structure. The solubility expression of nitrogen in the Fe-C-V-N system at 1 708 K was ωN = 0.058194–0.010367ωc+0.0055434ωv. Comparing the computing results with the experimental results, a satisfactory conclusion could be obtained. The analysis of the Fe-C-V-N system using this model showed that VN was present in a high temperature metal melt, which would reduce the action concentration of nitrogen obviously. It was consequently disadvantageous to the removal of nitrogen from hot metal.